Here are some wonderful tools for Upper Grades (7-12) aged children (we'll be adding more, and we take suggestions, too):

Reading:
Mrs. Scott's English Wiki - Dozens of great tools and ideas
UEN.org - Great interactive tools that supplement class activities
Lit 2 Go - Hundreds of classic books available as audio selections, many with activities

Math:
Mr Hansen's Math Wiki - Minarets High School, many great math ideas
The National Library of Virtual Manipulatives - Pre K-12 Algebra, Geometry and More\
Visual Math - online math lessons
Purple Math - more online math support

Thousands of excellent how to videos and lesson ideas:

www.Teachertube.com

For example: Teach Literary Devices with TV commercials, includes downloadable worksheet

Cool worksheets (old school still works!) http://www.eslprintables.com/